At an input station on an endless belt conveyor used for transporting coal, ore, sand, gravel, or other granular material, spillage of material over the edges of the belt can frequently present a substantial problem. The spillage is usually controlled by positioning skirtboards along the edges of the conveyor belt for some distance downstream of the input location. Because the edges of rigid skirtboards engaging the belt edges would create undue friction and cause excessive wear on the belt, as well as undue loading of the conveyor drive, it has been conventional practice to position each skirtboard a short distance above the edges of the belt and to mount a flexible apron on the skirtboard to close the resulting gap. Some prior art systems have provided for vertical adjustment of the aprons to compensate for wear on the apron edges that contact the moving belt. Skirtboards equipped with vertically adjustable aprons of rubber, canvas, or other resilient material are described in Roberts U.S. Pat. No. 2,593,610 issued Apr. 22, 1952 and in Clegg U.S. Pat. No. 3,499,523 issued Mar. 10, 1970. An improved conveyor skirtboard mounting is described in Gordon U.S. Pat. No. 4,231,471, issued Nov. 4, 1980.
While these previously known skirtboard and apron arrangements can provide effective control of spillage over the sides of the conveyor, some problems remain in fastening the aprons to the skirtboards. For example, previously known systems have not been capable of providing for quick release in a mounting construction that can accommodate substantial variations in apron thickness. The quick-release feature is necessary to minimize down time required by wear-related adjustments of the apron position. Similarly, maximum flexibility dictates that apron clamps be capable of handling a variety of apron thicknesses. Similar problems occur in other barrier mounting applications, including access cover mounts and the like.